Chem Basis: Steroids 3

Card Set Information

Author:
kyleannkelsey
ID:
268466
Filename:
Chem Basis: Steroids 3
Updated:
2014-03-30 18:19:32
Tags:
Chem Basis Steroids
Folders:
Chem Basis: Steroids 3
Description:
Chem Basis: Steroids 3
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user kyleannkelsey on FreezingBlue Flashcards. What would you like to do?



  1. A C21 ester is active at GC recptors?
    • False, it is a prodrug
    • Free C21-OH is required for corticoid binding
    • Must hydrolyze before activity can be achieved

  2. How can you alter the lipophilicity of this molecule?
    • Enhance lipophilicity: Esterify the C21 with a lipophilic acid
    • Reduce Lipophilicty: Esterify the C21 with an acid that will create a charge of 7.4

  3.  A lipophilic ester at the C21 effects what characteristics of this molecule?
    • More H20 insoluble
    • Reduces systemic side effects
    • Increases localization of action
    • Slows the OOA
    • Prolongs the DOA
    • Enhances topical use

  4. Why does a lipophilic ester at the C21 give the molecule more localized action?
    Higher Log P limits systemic distribution

  5.  Why does a lipophilic ester at the C21 give the molecule reduced systemic side effects?
    Higher Log P limits systemic distribution

  6. Why does a lipophilic ester at the C21 give the molecule reduced OOA?
    Slow release of the C21-OH from the ester prodrug form to the active free C21-OH form

  7. Why does a lipophilic ester at the C21 give the molecule a prolonged DOA?
    • Hydrolysis to the active C21-OH is slow
    • Resistant to C17 oxidation to the inactive 17 keto steroid
    • Does not concentrate in the kidney
    • Undergoes tubular reabsorption if it does make it to the kidney

  8. Why does a lipophilic ester at the C21 give the molecule better topical action?
    • High Log P allows for better skin penetration
    • Cannot readily redistribute or absorb (unless skin is broken)

  9.  What are lipophilic C21 ester prodrugs used for?
    • Internally: chronic therapy
    • Topically: for dermatitis

  10. Why are lipophilic C21 ester prodrugs a good choice for internal chronic therapy?
    Longer DOA = fewr doses = better compliance

  11. By what route would a lipophilic C21 ester prodrug be given?
    • Topically
    • PO
    • Inhalation
    • Oil based depo

  12. Would you need more or less drug to achieve appropriate action with an C21 ester prodrug and why?
    Less, due to the longer DOA

  13. Is this drug lipophilic or hydrophilic?
    • Lipophilic

  14.  Is this drug lipophilic or hydrophilic?
    • Lipophilic

  15. What is this function group called?
    Acetate

  16. A hydrophilic C21 prodrug ester has what characteristics
    • Useful IV and IM
    • Mostly charged at pH 7.4
    • Wide systemic distribution and side effects
    • Rapid OOA
    • Short DOA

  17. Why does a hydrophobic ester at the C21 give the molecule better distribution?
    Water soluble, so easily transported in the blood

  18. Why does a hydrophobic ester at the C21 give the molecule better IV and IM administration capabilities?
    Water soluble

  19.  Why does a hydrophobic ester at the C21 give the molecule a more rapid OOA than a lipophilic ester?
    • Easily absorbed into the plasma and transported
    • Esterases are readily available in the plasma

  20. Why does a hydrophobic ester at the C21 give the molecule a shorter DOA than a lipophic ester?
    • Water soluble = rapidly excreted by the kidney and not reabsorbed
    • Oxidation to 17-keto steroid is much faster since it is readily hydrolyzed by plasma esterases

  21. A hydrophobic ester at the C21 will be neutral or charged at physiological pH?
    Charged

  22. What routes of administration are available for a hydrophobic ester at the C21?
    PO, injection, inhalation and topical

  23. Why is a hydrophilic C21 ester prodrug less desirable topically than a lipophilic ester?
    • Greater systemic distribution and skin penetration
    • Leads to greater side effects

  24. Is this a lipophilic or hydrophilic prodrug?
    • Hydrophilic

  25.  Is this a lipophilic or hydrophilic prodrug?
    • Hydrophilic

  26. What is this group called?
    Sodium phosphate

  27. What is this group called?
    Sodium succinate
  28. What is a diether?
    • C21 ether + either a 17B or 16a ether
    • (picture is an example of a dipropionate ester)

  29.  The function group attached to the D ring in these images is classified as what type of group?
    Ketel (cyclic gem-diether)

  30. What characteristics must this Carbon have?
    No Hydrogens attached

  31. What is the specific name for this functional group?
    Acetonide

  32. Is this drug active or is it a prodrug?
    • Active

  33. What is the specific name for this functional group?
    Hexacetonide

  34. Is this drug active or is it a prodrug?
    • Prodrug

  35.  Do these functional groups need to hydrolyze to free –OH’s before the drug can be active at the corticoid receptors?
    No, only the C21 ether needs to be hydrolyzed

What would you like to do?

Home > Flashcards > Print Preview